If I had any sense I would stay out of this---but today I seem to be adequately senseless :hatoff:
My way of adjusting them was to loosen the three screws and turn (while cold) the body (CCW?) enough to just close the choke plate. Although I do not see it on yours, I believe they had a reference arrow molded into them that served as a reference and the nominal setting lined up with a marking on the die cast part of the housing.
I'll end my possible embarrassment there:rolleyes2: